A study found that older women who took calcium supplements to keep age-related bone damage at bay are increasingly susceptible to developing dementia. However, the increased risk is limited to women who have had a stroke or suffer from other illnesses that affect the flow of blood to the brain.

The study published Wednesday in the journal Neurology studied data of 700 women aged between 70 and 92 who didn’t have dementia.

“Our study is the first to show a relationship between calcium supplementation and increased risk for dementia in older women,” the study’s lead author Silke Kern of the University of Gothenburg in Sweden reportedly said.

The findings, however, don’t definitively prove that the calcium supplements directly cause dementia, Kern added. This holds true even among women who have had a stroke.

“These findings need to be replicated before any recommendations can be made,” Kern said.

The women involved in the study performed a number of psychiatric and cognitive tests, which included assessments of memory and reasoning skills at the start of the study and once again five years later. Of the 700 subjects, 450 got brain scans too.

At the start of the study, 98 women were taking calcium supplements and 54 had had a stroke. During the study, 54 more women had strokes and 59 developed dementia.

Of the 450 women who got brain scans, 71 percent had white-matter lesions, which are signs of strokes or cerebrovascular diseases, illnesses that affect the flow of blood to the brain.

Researchers found that women who took calcium supplements were twice as likely to develop dementia when compared to those who didn’t. This risk was limited to those who showed signs of existing cerebrovascular diseases or those who had experienced a stroke.

Women who had experienced a stroke and took calcium supplements were seven times as likely to develop dementia, the study found. Subjects who had white-matter lesions were thrice as likely to develop dementia if they took calcium supplements. But among women who had never experienced a stroke nor showed any white-matter lesions, consuming calcium supplements did not increase their likelihood of developing dementia

However, the researchers did not study the brain scans of the women at the end of the study thus failing to analyze how the supplements may have affected the white-matter lesions. The study also failed to analyze the amount of calcium the women consumed as part of their daily diet apart from their intake of calcium supplements. Calcium consumed as part of the daily diet can affect the body differently when compared to calcium supplements, the researchers said.